07--struts--上传文件

 1.index.jsp

<form action="upload.do" method="post" enctype="multipart/form-data">  标题：<input type="text" name="title"/><br/>  文件：<input type="file" name="myfile"/><br/>  <input type="submit" value="上传">  </form>

说明：

（1）enctype 属性规定在发送到服务器之前应该如何对表单数据进行编码。

application/x-www-form-urlencoded在发送前编码所有字符（默认）multipart/form-data

不对字符编码。

在使用包含文件上传控件的表单时，必须使用该值。

text/plain空格转换为 "+" 加号，但不对特殊字符编码。
（2）type---file

file定义输入字段和 "浏览"按钮，供文件上传。

2.ActionForm---UploadActionForm.java

package edu.tjpu.struts;import org.apache.struts.action.ActionForm;import org.apache.struts.upload.FormFile;public class UploadActionForm extends ActionForm {private String title;//文件采用FormFile声明private FormFile myfile;public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public FormFile getMyfile() {return myfile;}public void setMyfile(FormFile myfile) {this.myfile = myfile;}}

说明：

（1）文件的上传收集采用FormFile来收集，FormFile是一个接口，里面定义了用于文件的各种方法。

（2）FormFile.java源码

package org.apache.struts.upload;import java.io.InputStream;import java.io.IOException;import java.io.FileNotFoundException;/** * This interface represents a file that has been uploaded by a client. It is * the only interface or class in upload package which is typically referenced * directly by a Struts application. */public interface FormFile{    /**     * Returns the content type for this file.     *     * @return A String representing content type.     */    public String getContentType();        /**     * Sets the content type for this file.     *     * @param contentType The content type for the file.     */    public void setContentType(String contentType);        /**     * Returns the size of this file.     *     * @return The size of the file, in bytes.     */    public int getFileSize();        /**     * Sets the file size.     *     * @param fileSize The size of the file, in bytes,     */    public void setFileSize(int fileSize);            /**     * Returns the file name of this file. This is the base name of the file,     * as supplied by the user when the file was uploaded.     *     * @return The base file name.     */    public String getFileName();        /**     * Sets the file name of this file.     *     * @param fileName The base file name.     */    public void setFileName(String fileName);        /**     * Returns the data for the entire file as byte array. Care is needed when     * using this method, since a large upload could easily exhaust available     * memory. The preferred method for accessing the file data is     * {@link #getInputStream() getInputStream}.     *     * @return The file data as a byte array.     *     * @exception FileNotFoundException if the uploaded file is not found.     * @exception IOException           if an error occurred while reading the     *                                  file.     */    public byte[] getFileData()            throws FileNotFoundException, IOException;        /**     * Returns an input stream for this file. The caller must close the     * stream when it is no longer needed.     *     * @exception FileNotFoundException if the uploaded file is not found.     * @exception IOException           if an error occurred while reading the     *                                  file.     */    public InputStream getInputStream()            throws FileNotFoundException, IOException;        /**     * Destroys all content for the uploaded file, including any underlying     * data files.     */    public void destroy();    }

3.Action---TestUploadAction.java

package edu.tjpu.struts;import java.io.FileOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.struts.action.Action;import org.apache.struts.action.ActionForm;import org.apache.struts.action.ActionForward;import org.apache.struts.action.ActionMapping;import org.apache.struts.upload.FormFile;public class TestUploadAction extends Action {@Overridepublic ActionForward execute(ActionMapping mapping, ActionForm form,HttpServletRequest request, HttpServletResponse response)throws Exception {UploadActionForm uaf=(UploadActionForm)form;String tile=(String)uaf.getTitle();FormFile myfile=uaf.getMyfile();if(myfile!=null){FileOutputStream fos=new FileOutputStream("d:\\"+myfile.getFileName());fos.write(myfile.getFileData());fos.flush();fos.close();}return mapping.findForward("uploadfile");}}

说明：

（1）首先是类型转换为UploadActionForm；

（2）获取标题和文件--FormFile类型；

（3）通过getFileData（）方法获取内容写入到磁盘。

4.struts-config.xml文件

<struts-config><form-beans><form-bean name="uploadForm" type="edu.tjpu.struts.UploadActionForm"></form-bean></form-beans><action-mappings><action path="/upload"type="edu.tjpu.struts.TestUploadAction"name="uploadForm"scope="request"><forward name="uploadfile" path="/upload_success.jsp"></forward></action></action-mappings></struts-config>

说明：

（1）这里的path 对应的index.jsp表达提交处理的地址；

（2）name对应于ActionForm中的名

（3）<forward>name属性值对应于Action返回的值

（4）交到upload_success.jsp去处理

 

（5）upload_success.jsp

<body>   <h1>上传显示结果</h1>   标题：${uploadForm.title }<br/>   文件名：${uploadForm.myfile.fileName }<br/>  </body>

要注意通过EL表达式输出时的格式。

 

总结：

（1）ActionForm中使用FormFile来接受上传的数据；

（2）在Action中使用FormFile接受从ActionForm中传递来的数据，并用数据流输出到磁盘；

（3）文件的上传可以通过<controller></controller>配置上传参数，比如maxFileSize、 nocache、 bufferSiz等。